This application is based on and claims priority under 35 U.S.C. xc2xa7 119 with respect to Japanese Application No. 2001-300062 filed on Sep. 28, 2001, Japanese Application No. 2001-300063 filed on Sep. 28, 2001, and Japanese Application No. 2001-300064 filed on Sep. 28, 2001, the entire content of which are incorporated herein by reference.
The present invention relates to an opening and closing mechanism. More particularly, the present invention pertains to an opening and closing mechanism for opening and closing a cover for vehicle such as a back door of a one-box car and a sunroof for a vehicle.
A known opening and closing mechanism for vehicle opening is disclosed in Japanese Patent Application Laid-Open No. 2000-335245. According to the known opening and closing mechanism for vehicle opening, actuation force from an electric motor is transmitted to a slider member via a worm fixed to the electric motor, a worm wheel engaged with the worm, and a pinion gear formed coaxially with the worm wheel.
The approximately rectangular shaped slider member is a plate member and a rack is formed on a rim of one of a pair of longer sides of the slider member. The actuation force to the slider member is input into the rack. Longitudinal guiding grooves are formed on the slider member in the longitudinal direction on the central portion of the plate width. By engaging the guiding groove with two guide pins having expanded head portion, the slider member receiving the actuation force performs linear reciprocating movement.
An axis support portion which is formed by bending the slider member at right angle is provided on approximately central portion of the other side of pair of sides of the slider member. That is, the axis portion is attached having a predetermined height relative to a body portion. An arm member connected to a door side is swingably pivoted on the axis portion. In accordance with the reciprocating movement of the slider member, the arm member is swung or retracted relative to the vehicle body to open or close the vehicle door.
With the construction of the known opening and closing mechanism for vehicle opening disclosed in Japanese Patent Application Laid-Open No. 2000-335245, the actuation force generated in the electric motor is transmitted to the slider member via the engagement between series of gears. Thus, in order to reduce the backlash and to prevent the disengagement of gears, each gear has to be arranged in accurate positions and the accurate positioning has to be maintained over a long period of time.
Accordingly, effective opening and closing mechanism could not be constructed due to the complexity for assembling the opening and closing mechanism and the necessity for reinforcing the attaching portion of the gears.
Further, according to the known opening and closing mechanism for vehicle opening disclosed in Japanese Patent Application Laid-Open No. 2000-335245, the rack and the axis portion is positioned offset from each other. In addition, because the axis portion has the predetermined height relative to the body portion of the plane slider member, portions slidably receiving the slider member with two guide pins is deviated from the plane surface including the rack and the axis portion. That is, when reciprocating the slider member, the force to rotate the slider member on the common plane surface of the body of the slider member and the force to lift up the slider member in the external direction of the plane surface are always affecting on the slider member around the guide pin slidably receiving the slider member as a fulcrum point.
Thus, it is necessary to reinforce the attaching structure of the guide pin and to thicken the slider member in order to eradicate the shake of the slider member derived from the above mentioned two kinds of force.
Further, the known opening and closing mechanism for vehicle opening disclosed in Japanese Patent Application Laid-Open No. 2000-335245 shows an example for applying the opening and closing mechanism on a back door which is opened upwardly. In this case, the load applied on the arm member is varied depending on the opening angle of the back door. Also, because a sealing member is provided between the back door and the vehicle body in most of case, for closing the back door completely it is necessary for deforming the sealing member to apply large force at a closing up position.
Notwithstanding, according to the known opening and closing mechanism for vehicle opening disclosed in Japanese Patent Application Laid-Open No. 2000-335245, the actuation force generated by the electric motor is decelerated to increase the torque by a constant ratio by the series of gear members and transmitted to the arm member. Thus, for example, the lack of the actuation force of the electric motor may be caused when the motion of a hinge portion of the back door becomes heavy due to the dust and dirt and the hardening of the sealing member by aging. For overcoming these defects, applying electric motor with larger output capacity is not favorable because of the increase in size and the increase in manufacturing cost.
Another known opening and closing mechanism is disclosed in U.S. Pat. No. 6,142,551. According to the known opening and closing mechanism disclosed in U.S. Pat. No. 6,142,551, the actuation force from an electric motor is transmitted to a slider member via a worm fixed on the electric motor, a worm wheel engaged with the worm, a gear coaxially formed with the worm wheel, and other gears of a gear train.
The long slider corresponds to a plate member and a rim of one of a pair of loner sides thereof is formed with a rack. The actuation force to the slider member is input into the rack from a final gear of the gear train. One end of the slider member is penetrated through inside of a swing case supported coaxially with the final gear. The slider member is held between the final gear and a holding roller in the swing case for reciprocating while swinging in accordance with the rotation of the rack. An approximately arc shaped link member is connected to the slider member. and a vehicle door is connected to the link member. With this construction, the actuation force from the electric motor is transmitted to the vehicle door.
The known opening and closing mechanism disclosed in U.S. Pat. No. 6,142,551 is, for example, installed in a rear ceiling portion of the vehicle. In this case, it is preferable to construct the opening and closing mechanism as small as possible in order to ensure large interior space.
Notwithstanding, in the known opening and closing mechanism disclosed by U.S. Pat. No. 6,142,551, an extending direction of pivotal axis of each gear of a series of gears, an extending direction of connecting axis of the sliding member and the link member, and an extending direction of the pivotal axis of the back door are all positioned parallel to one another. That is, the each gear and a swing plane including the swinging slide member and the link member are all arranged parallel to each other. The back door has a construction to open upward and the swing plane of the back door is extended in perpendicular direction. Thus, the opening and closing mechanism of U.S. Pat. No. 6,142,551 installed on the rear ceiling of the vehicle is projected towards the downward of the interior space. In particular, a gear diameter may be predetermined to be large for increasing the deceleration ratio of the motor in order to open and close the large back door with heavy weight. In that case, the projecting amount of the open and closing mechanism into the interior space is further increased.
A need thus exists for an opening and closing mechanism which effectively and securely transmits the actuation force, operates with large actuation force at open position and closed position, and provide efficient use of an interior space.
In light of the foregoing, the present invention provides an opening and closing mechanism for a cover for vehicle which includes a crank gear rotatable about a crank axis center for opening and closing the cover for vehicle, a slider reciprocating along a guide member, a crank arm pivoted on a crank pin of the crank gear on one end and pivoted on a slider pin of the slider on the other end, and a cover operation member provided between the slider and the cover for vehicle to be swingable relative to the slider for cooperating the slider and the cover for vehicle.
According to another aspect of the present invention, an opening and closing mechanism for a cover for vehicle includes a crank gear rotatable about a crank axis center for opening and closing the cover for vehicle, a slider reciprocating along a guide member, a crank arm pivoted on a crank pin of the crank gear on one end and pivoted on a slider pin of the slider on the other end, a cover operation member provided between the slider and the cover for vehicle to be swingable relative to the slider for cooperating the slider and the cover for vehicle, a first rotation member rotatable about a first rotational axis center which is parallel to or coaxial to the axis center of the operation member pivotal axis, a first guide surface formed on the guide member for guiding the first rotation member, a second rotation member rotatable about a second rotational axis center which is parallel to or coaxial to an axis center of the slider pin, a second guide surface formed on the guide member for guiding the second rotation member, an operation member pivotal axis for pivoting the cover operation member on the slider, and an output shaft of a drive motor for driving the crank gear, the output shaft positioned on a side opposite to an interior space of the vehicle relative to the crank gear.